Our gut flora is determined by what we eat, for good or for ill.
When we eat meat, dairy, eggs, and seafood, our gut flora can take certain components in them (carnitine and choline) and produce something that ends up as a toxic compound called TMAO, which may set us up for a heart attack, stroke, and death.
So, give people two eggs, and you get a spike of TMAO in their bloodstream within hours of consumption. Because gut bacteria play a critical role in this process, though, if you then give them a week of antibiotics to wipe out their gut flora, and re-feed them two more eggs, nothing happens. No TMAO in their bloodstream because they have no egg-eating bacteria to make it. But give it a month for their gut bacteria to start to grow back, and the eggs start to cause TMAO production once again.
It’s the same thing with meat. Give people the equivalent of an 11-ounce steak, and TMAO levels shoot up in the blood. But feed them the same amount after a week of antibiotics, and nothing happens. So, to run into problems, you need both the meat and the meat-eating bugs. That’s why you can feed a vegan a sirloin, and they don’t produce TMAO within their body. They just don’t have the meat-eating bugs in their gut.
Okay, now this should all be old news for those who have been following the science. The reason for this video is to show that this phenomenon happens the other way around too. When we eat whole plant foods, like fruits, vegetables, whole grains, and beans, along with nuts and seeds, our gut flora can take certain components in them (fiber and resistant starch) and produce short-chain fatty acids, which can set us up for the prevention of human diseases. Short-chain fatty acids, like butyrate, can help seal up a leaky gut, fight inflammation, prevent weight gain, improve insulin sensitivity, accelerate weight loss, and fight cancer.
But these benefits rely on two things—eating fiber and having fiber-feeding bugs—just like the detrimental effects from TMAO required not only eggs, dairy, or meat but also the eggs, dairy, or meat-munching bugs.
Check this out. If you give people whole intact grains––in this case barley kernels, also known as barley groats (three servings a day, like I recommend in my daily dozen app)––within just three days of eating that extra 30+ grams of fiber and resistant starch, their gut bugs were so happy and produced so many short-chain fatty acids that people’s insulin levels improved by 25 percent, which means their bodies needed to produce less insulin to take care of the same amount of white bread, while still dampening the blood sugar spike. But this was on average.
Some people responded to all that extra fiber with beautiful dips in blood sugar and insulin responses, but in others, the same amount of fiber and resistant starch didn’t work at all. Why? Because you don’t just need fiber, but fiber-feeding bugs like Prevotella. How do you get more Prevotella so you can take full advantage of the health benefits of plants? Eat more plants. Prevotella abundance is associated with long-term fiber intake.
If you look at rural African children eating 97 percent whole food, plant-based diets, their Prevotella is off the charts compared to kids eating standard Western diets, and this is reflected in the amount of short-chain fatty acids they are churning out in their poop.
In the industrialized world, it’s those habitually eating vegetarian and vegan that promotes the enrichment of ﬁber-eating bacteria in the gut. Here’s the relative Prevotella abundance between those who eat meat, no meat, or all plants.
This may help explain the worse inflammatory profile in omnivores than in vegetarians. Based on the findings relative to bacteria abundance, the researchers “suggest that exposure to animal foods may favor an intestinal environment which could trigger systemic inflammation and insulin resistance-dependent metabolic disorders” such as type 2 diabetes. And it’s the reduced levels of inflammation that may be the key factor linking a plant-based gut microbiota with protective health benefits. Yeah, but can’t meat-eaters eat lots of plants too? Omnivores have “constraints on diet-dependent gut microbiota metabolite production.” In other words, it’s the flipside of the vegan eating a steak. They can eat all the fiber they want, but may be lacking in fiber-munching machinery.
At low levels of fiber intake, the more you eat, the more of the beneficial short-chain fatty acids are made. But at a certain point, your available fiber-feeders are maxed out, and there’s only so much you can benefit. But those habitually eating a plant-based diet have been cultivating the growth of these fiber-feeders, and the sky’s the limit––unless, of course, you’re eating vegan junk. But a whole food, plant-based diet should be “effective in promoting a diverse ecosystem of beneﬁcial bacteria to support both our gut microbiome and overall health.”
Republished from NutritionFacts.org
- Wang Z, Klipfell E, Bennett BJ, et al. Gut flora metabolism of phosphatidylcholine promotes cardiovascular disease. Nature. 2011;472(7341):57-63.
- Tang WHW, Wang Z, Levison BS, et al. Intestinal microbial metabolism of phosphatidylcholine and cardiovascular risk. NEJM. 2013;368(17):1575-84.
- Koeth RA, Lam-Galvez BR, Kirsop J, et al. L-carnitine in omnivorous diets induces an atherogenic gut microbial pathway in humans. J Clin Invest. 2019;129(1):373-87.
- Koeth RA, Wang Z, Levison BS, et al. Intestinal microbiota metabolism of l-carnitine, a nutrient in red meat, promotes atherosclerosis. Nat Med. 2013;19(5):576-85.
- O’Keefe SJD, Li JV, Lahti L, et al. Fat, fibre and cancer risk in African Americans and rural Africans. Nat Commun. 2015;6(1):6342.
- Prasad KN, Bondy SC. Dietary Fibers and Their Fermented Short-Chain Fatty Acids in Prevention of Human Diseases [published online ahead of print, 2018 Oct 15]. Mech Ageing Dev. 2018;S0047-6374(18)30013-7.
- Zhang LS, Davies SS. Microbial metabolism of dietary components to bioactive metabolites: opportunities for new therapeutic interventions. Genome Med. 2016;8(1):46.
- Nilsson AC, Johansson-Boll EV, Björck IME. Increased gut hormones and insulin sensitivity index following a 3-d intervention with a barley kernel-based product: a randomised cross-over study in healthy middle-aged subjects. Br J Nutr. 2015;114(6):899-907.
- Kovatcheva-Datchary P, Nilsson A, Akrami R, et al. Dietary fiber-induced improvement in glucose metabolism is associated with increased abundance of prevotella. Cell Metab. 2015;22(6):971-82.
- David LA, Maurice CF, Carmody RN, et al. Diet rapidly and reproducibly alters the human gut microbiome. Nature. 2014;505(7484):559-63.
- De Filippo C, Di Paola M, Ramazzotti M, et al. Diet, environments, and gut microbiota. A preliminary investigation in children living in rural and urban burkina faso and italy. Front Microbiol. 2017;8:1979.
- De Filippis F, Pellegrini N, Vannini L, et al. High-level adherence to a Mediterranean diet beneficially impacts the gut microbiota and associated metabolome. Gut. 2016;65(11):1812-21.
- Wang F, Wan Y, Yin K, et al. Lower circulating branched-chain amino acid concentrations among vegetarians are associated with changes in gut microbial composition and function. Mol Nutr Food Res. 2019;63(24):e1900612.
- Franco-de-Moraes AC, de Almeida-Pititto B, da Rocha Fernandes G, Gomes EP, da Costa Pereira A, Ferreira SRG. Worse inflammatory profile in omnivores than in vegetarians associates with the gut microbiota composition. Diabetol Metab Syndr. 2017;9:62.
- Glick-Bauer M, Yeh MC. The health advantage of a vegan diet: exploring the gut microbiota connection. Nutrients. 2014;6(11):4822-38.
- Wu GD, Compher C, Chen EZ, et al. Comparative metabolomics in vegans and omnivores reveal constraints on diet-dependent gut microbiota metabolite production. Gut. 2016;65(1):63-72.
- Tomova A, Bukovsky I, Rembert E, et al. The effects of vegetarian and vegan diets on gut microbiota. Front Nutr. 2019;6:47.